Apparatus for extruding matter



June 15, 1937. E. w. LARSEN APPARATUS FOR EXTRUDING MATTER Filed Oct. 12, 1932 5 Sheets-Sheet 1 June l5, 1937. E WLARSEN APPARATUS Fon XTRUDING MATTER Filed Oct. l2, 193?, 3 SheebS--Sheet 2 June15,1937. f A, E 'W LARSEN 2,034,149

APPARATUS FORl EXTRUDING MATTER Filed oct. 12, 1932 sheets-Sheet 5 Patented Jane 15, 1937 APPARATUS FOR EXTRUDING MATTER Einer W. Larsen,

Chicago,

lll., assigner to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application october 12, 1932, serial No. 637,465

18 Claims.

This invention relates to apparatus for extruding matter, and more particularly to apparatus for continuously extruding a metallic sheath around a cable or core in strand form.

An object of the invention is to provide an improved apparatus for continuously extruding matter.

' Another object of the invention is to provide an improved apparatus for continuously sheathing cables or cores in strand form.

One form of apparatus embodying the features of the invention comprises a plurality (preferably two) of hydraulically actuated piston type extrusion pumps arranged to receive matter to be extruded from a supply thereof and discharge the same intoy a common extruding chamber. The hydraulic circuit for actuating the pumps is arrangedv so that the forward strokes of the pistons overlap each other and the hydraulic pressure for the forward strokes of all pistons is supplied by a single constant delivery pump, whereby the sum of the forward stroke displacement rates of the pistons is always uniform.YY

Thus, the matter to be extruded is continuously 25 forced into the extruding chamber at a constant rate and consequently the matter at the dis- -charge end of the chamber is continuously extruded through the die at a constant rate. This arrangement and method of driving the extrusion pumps permits the rate of extrusion to be readily and conveniently controlled by simply regulating the displacement of the constant delivery pump. Also, it permits the regulation of the temperature 35 of the matter within the extruding chamber from the extruding pressure. Furthermore, it permits the convenient and accurate regulation of extruding pressure, as by means of safety or relief valves, whereby the extruding pressure is posi- 40 tively prevented from exceeding a predetermined safe limit so as not to build up disruptive stresses within the extrusion chamber.

The invention further contemplates means for maintaining the matter within the extruding 5 chamber in a liquid state until very near the extrusion point, whereby the extruding pressure may be vreduced to a practicable minimum.

Other features and advantages of this invention will more fully appear) from the following detailed description taken in connection with the accompanying drawings, in which Fig. 1 is a fragmentary plan View, partly in section, of an extruding apparatus which em- 55 bodies the invention;

Fig. 2 is a transverse vertical section, on a reduced scale, taken on the line 2 2 of Fig. l;

Fig. 3 is a fragmentary detail section, on an enlarged scale, taken on the line 3 3 of Fig. 1;

60 Fig. 4 is a diagrammatic view of the hydraulic lcircuit for controlling and operating the extrusion pumps;

Fig. 5 illustrates diagrammatically a mechanism for controlling the temperature of the matter within the extrudlng chamber, and

Fig. 6 illustrates diagrammatically an alternative form of mechanism for controlling the temperature of the matter being extruded.

'I'he apparatus illustrated in the drawings and' hereinafter described is particularly applicable for applying a lead alloy sheath'to cable cores.

Referring to Figs. 1 and 2, the reference character I0 designates a base plate, shown fragmentarily, upon which is mounted at one end an extrusion head, indicated generally by the reference character the head being rigidly secured to the base plate by bolts |2. The head comprises a tubular block I 3 provided withan axially arranged annular extrusion chamber I4, which is contracted at its left end to form a discharge opening I5. Shrunk, as indicated at I6, onto the front end of the block I3y is a ring I1, an inner annular surface |8 of which abuts an outer annular surface of a peripheral flange I9 formed on the block (Fig. 1). l Surrounding the block I3 at the right of the ring I1 is a one piece housing provided with a back wall 2|. The extrusion chamber I4 at its right or inlet end communicates by means of passages 22 with a pair of diametrically opposed tapered depressions 25 formed in the right end wall of the block I3 (Fig. 2). The depressions 25 are aligned .with

similarly arranged openings 26 provided in the.

to flt the tapered depressions 25 of the block I3.

'I'he longitudinal axes of the pumps 28 are inclined at equal angles to the axis of the extrusion chamber I4, the right end wall ofthe block I3 and the end wall 2| of the housing 2D abutting therewith, and which have formed therein the depressions 25 and openings 26, respectively, forreceiving the cylinders 21 of the pumps, being arranged perpendicular to the pump axes.

Supporting frames 29 of the pumps 28 are secured to the back wall 2| of the housing 20 by a plurality of bolts 32, while the housing 20 is secured to the ring I1 by a plurality of screws 33. At their right ends the frames 29 are supported on i-beams (not shown) secured to the base plate IIJ. With this construction for supporting the pumps 28 in operative relation with the extrusion block I3, it will be observed that there is no necessity for any screw threaded apertures for screws or bolts in the extrusion block.

This results in an extrusion block having a maximum resistance to disruptive stresses during the extruding operation.

'I 'he discharge opening I5 of the extrusion 5 chamber I4 has associated therewith a. core tube 34 and a die 35. 'Ihe core tube 34 is rigidly secured axially of the chamber I4 in a sleeve 36 formed integral with the block I3, the inner diameter of the core tube being substantially the diameter of a cable core 3,9 to be sheathed and I which in the operationof the apparatus is drawn through an opening in the back wall 2| of the housing 20, an aligned opening in the block I3 and then through the core tube and the die 35.

The die 35 is slidably carried and accurately fitted without any lateral play in a shouldered aperture 40 in a die holder 4I interposed between the block I3 and a clamping `ring 42, the die holder being outwardly shouldered at its inner end and fitted into cooperating inner shoulders at the forward end of the block thus forming the left end wall of the extrusion chamber I4. Abutting the left end of the die is an adjustable sleeve 43 threadedly carried in the die holder 4I, the

inner end of the sleeve being fitted with a cable guiding ring 46 having an internal diameter corresponding to the diameter of the sheathed cable. At its outer end the sleeve 43 is provided with a plurality of attened faces 41 adapted to receive a wrench, which may be used to rotate and thereby adjust the sleeve longitudinally in the die holder 4I. A movement inwardly of the sleeve 43 will slide the die 35 in a similar direction and thereby reduce the distance between the cooperating opposed end faces of the die and the core tube 34 which space forms the discharge opening I5 of the extrusion chamber I4. An outward movement of the sleeve'43 will permit the die 35 to follow, through the thrust thereagainst of matter or alloy being extruded at the discharge opening I5, and thereby increase the size of the Ydischarge opening. This permits the operator to control the cross-sectional area of alloy sheath being extruded through the discharge opening I5 and around the cable core 39. The clamping ring 42 is secured to the ring I1 by a plurality of bolts 43, the ring I1 as hereinbefore described, being shrunk' onto the block I3. Wedged or otherwise suitably secured in the extrusion chamber I4 between the outer and inner peripheries of the sleeve 36 and the block I3, respectively, and in front of the outlet ends of the passages 22 is a pair of rectangulariplates 50 (Fig. 2). 'I'he plates 56 serve to diffuse the incoming'molten alloy around the extrusion chamber I4 thereby causing the alloy to move uniformly toward the discharge opening I5.

' Since the axis of the die 35 is coincident with the axis of the core tube 34, and the molten alloy is uniformly disposed around the discharge opening I5 it follows that any alloy extruded therethrough will form a sheath of uniform thickness around the cable core 33. The cable core 39, of course, will be drawn by the lead sheath through the apparatus at a rate of speed equal to the flts within an aperture in the supporting frame 29. The cylinders 21 are each provided with a central longitudinal bore 5I extending from the right end of the cylinder to a point adjacent the left end thereof (Figs. 1 and 3) within which is slidably journaled a plunger 53 adapted to be reciprocated therein so that itmay force the alloy, to be extruded, into thev annular extrusion chamber I4. The alloy to be extruded is supplied to the cylinders 21 by way ofa common manifold 54 (Fig. 2) which is connected by means of a pipe'55 to a suitable receptacle or supply source (not shown) provided with means to keep the alloy in a fused state so that it may gravitate by way of the pipe 55, manifold 54, and inlet passages 56, formed in the left end of each of the cylinders, to the bores 5I thereof. A valve 51 disposed in the pipe 55 provides means whereby the operator may shut off the flow of fused alloy to the cylinders 21.

To prevent a back flow of the fused alloy from the cylinders 21 through the passages 56 and into the common manifold 54, valve devices 66 are l6I) and 62 are arranged substantially parallel to the axis of the associated cylinder bore 5I. Also, both ports are formed in the forward end wall of the cylinder and do not enter the side walls of the cylinder bore.

'I'his arrangement of the inlet and outlet ports of the cylinder bores 5I, it will be apparent, pro- In l vides an economical cylinder construction ywhich reduces concentrated stresses in the cylinder. the particular arrangement shown in the drawings the inlet port is offset with respect to the axis of the cylinder bore 5I and the outlet port is coincident therewith at its outer end with its inner end offset similar to the inlet port.

Each of the valve devices 66 and 62 comprises avalve cage 63 .mounted in the cylinder at its respective port. A length oi' drill rod 64 is wedged in the cylinder bore 5I and against the closed end wall of the cage 63 to secure the same in position. Each of the valve cages 63 is provided with a central aperture 65 through which -the fused alloy must pass on its way into or out of the cylinder bore 5I. Disposed axially within the apertures 65. of the valve cages 63 and. re-

ciprocable longitudinally thereof are balls 61 adapted to engage valve seats formed in the inlet and outlet ports at the inner ends oi' the passages 56 and 6I.

mm the foregoing detailed .description of the pumps 28, it is apparent that if one of the plungers 53 is reciprocated in its cylinder 21, there will be an intermittent iiow of fused alloy from the supply receptacle (not shown) lthrough the lcylinder, and thence into the annular extrusion chamber I4, the valve devices 66 and 62 acting to control the ilow of fusedalloy to and from the cylinder 21.

In accordance with a feature of the present invention, the pumps 26 are driven so that the forward strokes of their plungers 53 overlap, whereby the fused alloy is continuously supplied to the extrusion chamber I4. Also, a single constant displacement pump supplies the pressure fluidA yperipheral surface of the block forms a heating i for the forward strokes of both plungers 53, whereby the sum of their forward stroke displacement rates is constant. "I'hus, the fused alloy is continuously supplied to the extruding chamber I4 and extruded therefrom at a constant rate.

rIhe means for driving the extrusion pumps 28 comprises a pair of hydraulically actuated pistons 68 reciprocable in cylinders 69 carried upon thexsupporting frames 29, the plunger 53 of each pump being attached at its right end to one of the pistons. Referring to Fig. 4 which illustrates diagrammatically the hydraulic circuit for controlling and operating the pistons 68, which actuate the pumps 28, a pair of oilpumps are indicated at 18 and 1|. The pumps 18 and 1| are preferably of the adjustable pressure and displacement type and may be of any suitable well known form capable ofdelivering a constant 'displacement of mud at adjustable limiting pressures when operated at a constant R. P. M. Valves 14 and 15 are transfer or reversing valves having pistons 16 and l11, respectively, locked together as indicated at 18 and actuated by hydraulic pressure. The valve '|4 serves to control the forward strokes of the plungers 53 of the extrusion pumps 28 and valve 15 controls the return strokes thereof. A mechanically actuated pilot valve 19 having a piston 80 controls the timing or reversal of the hydraulically actuated valves 14 and 15, the piston 88 being flexibly connected as indicated at 8| to the free end of a rocker arm 83 pivoted at a point 84 intermediate the pumps 21 to a bracket 85 (Fig. 1) extending between the pump frames 29 and attached thereto. Fixed to the underside of the rocker arm 83 is a bar 88, opposite ends of which are alternately engaged by adjustable screws or strikers 81, carried by the plungers 53, the engagement occurring only at the forward ends of the plunger strokes.

It will be apparent that means other than hydraulic power controlled by the mechanically actuated pilot valve 19 can be employed for actuating the timing or reversing valves 14 and 15.

`ered a portion thereof.

53 or leverage mechanism actuated by the movement of the plungers could be employed with equally good results.

Each of the extrusion pumps 28 is provided with means for packing the clearance which must be provided between each plunger 53 and a gland member 92 (Fig. 1) threaded into the associated cylinder 21 and which may be consid- This packing means in each instance comprises an annular recess 93 formed in the gland member 92, adapted to collect and retain the fused matter or alloy seeking to escape by way of the above mentioned clearance. The alloy so collected tends to revert to its solid state, but to insure such a change of state, an annular chamber 94 is provided in the gland member 92 into which a fluid coolant may be introduced by means comprising a plurality of nozzles 95 communicating with the chamber 94, the coolant being circulated through the chamber byineans (not shown) connected to the nozzles. A fluid coolant so introduced into the chamber 94 will lower the temperature of any fused alloy collected in the annular recess 93 and cause it to solidify. 'I'he solidified alloy will then pack the extrusion pump 28.

The housing 28 surrounding the tubular extrusion block |3 (Figs. 1 and 2) is provided with an inner annular channel 96 which with the chamber 91 adapted to receive'a heating medium, the chamber being disposed around the inlet end of the extrusion chamber I4 of the block I3. The heat from a gas burner may be utilized as the heating medium and circulated through the chamber by a blower, the burner and blower being associated with one of a-pair of pipes 98 connected to opposite sides of the chamber 91. In Fig. 5 the burner and blower are illustrated diagrammatically. The housing 28 and the pipes 98 are insulated with a suitable heat retaining material 99, such as asbestos. This provides means whereby sufficientV heat may be conducted from the chamber 91' through the wall of the block I3 and to the extrusion chamber |4 for preventing solidioation of the fused alloy upon its entrance into the extrusion chamber and while passing therethrough until it reaches a point indicated by the broken lines |88 adjacent the extrusion point formed by the discharge opening I5 at the contracted left end of the extrusion chamber.

Formed in the die holder 4| which forms the left end wall of the extrusion chamber I4, is a plurality of circularly disposed recesses |8I, two of which are shown in Fig. 1. Extending into each of the recesses I8| is a tube |82 which is smaller in diameter than that of the recess and spaced at its inner end from the end wall thereof, the tubes being secured to a cap member |83 xed to the die holder 4|.. The outer ends of the tubes |82 communicate with an annular chamber |84 formed in the cap member |83 while the outer ends of the recesses communicate with an annular chamber formed in the die holder 4I and the cap member, the tubes extending through the chamber |85. Communicating with v the chambers |84 and |85 are pipes |86 and |81, respectively, the pipe |86 being connected to a supply source (not shown) of a suitable fluid coolant, whereby the coolant may be introduced into the chamber |84 circulated through the tubes |82, the recesses |8I, the chamber |85 and llitsing out through an exhaust or return pipe It will be apparent that by the arrangementl Just described the coolant is supplied to the forward or extruding end only of theextruding chamber I4, and thus at all times, only a small portion of the alloy immediately adjacent the extruding point is in a solidified state. By controlling the temperature of the heating medium .received by the chamber 81 and also that of the coojant entered in'to the die holder 4| a suicient supply of alloy in its solid state in the form of a slug extending from the point |88 to the discharge opening I5 can be constantly stored in the annular extrusion chamber to avoid the possibility of any alloy passing out in its fused state through the discharge opening. By varying the temperatures of the fluid coolant and the heating medium the point |88 in the extrusion chamber |4 where the fused alloy reverts to a solidified state canbe varied' to maintain the slug continually being formed of minimum length and thus the pressure needed to displace the solidified alloy longitudinally in the extrusion chamber I4, through the discharge opening I5 and around the cable core 39 is reduced to a practicable minimum.

'I'he operation' of the herein described hydraulically actuated extrusion pumps 28, assuming that the oil pumps 18 and 1| have been individually adjusted or set to deliver a predetermined constant volume of fluid of the reouired'limited pressure, is as follows:

In the position of the parts shown in Figs. 1

and 4 and referring particularly to Fig.v 4, the left hand plunger 53 has just completed its upward or forward pumping strokeand has actuated the rocker arm 83m a clockwise direction, thereby shifting the valve piston 80' of the pilot valve 19 from its extreme upper position, shown fragmentarily in dotted outline, into its extreme lower position as shown. In this position of the valve piston 80 low pressure from an auxiliary pump in the oil pump 1| is directedlby a pipe |08 through a chamber |09 of the valve 19 and a pipe to a chamber of the transfer or reversing valve 14 which lserves to shift its valve piston 16 and the valve piston 11 Lof the valve 15, which are locked together, from their extreme left position, shown fragmentarily in dotted outline, to their extreme right position as shown. In this last position of the valve pistons 16 and 11,` high pressure fluid from the oil pump 10 is directed by a pipe |I3 through a chamber ||4 of the valve 14 and a pipe ||5 to the lower end of the fright cylinder 69, the piston 63 and plunger 53 of which have just completed their return stroke. Simultaneously with the vdirection of high pressure from the pump 10 to the lower end of the right cylinder 69, a suitable pressure from the pump 1| is directed by a.' pipe ||6 through a chamber I|1 of the valve 15 and a pipe |20 to the upper end of the left cylinder 69, the piston 68 and plunger 53 of which as hereinbefore described have just completed their forward or pumping stroke4 Upon this shifting 'of the valve pistons 90, 16 and 11 it will be apparent that the right and left plungers 53 will be moved` upwardly and downwardly, respectively, as viewed in Fig. 4, the upward or forward stroke of the rightplunger 53 pumping fused matter or alloy from ,the bore of the associated extrusion pump into the extrusion chamber I4, through the discharge opening I5 and around thecore 39 and the downward or return stroke of the left plunger drawing a charge of fused alloy from the supply (not shown) into the bore 5I `oi! the associated extrusion pump 23 ready for the next forward pumping stroke of the plunger, all inthe manner previously described. The exhaust oil from the upper end of the right cylinder 69 is returned to the sump of the'pump 1| by way of a pipe |2|, a chamber |22 of the valve 15 and a pipe.

|23 while the exhaust oil from the lower end of the deft cylinder 69 is returned to the sump of the pump by way of a pipe |24,.a chamber forward stroke of the right plunger 53 the associated striker 91 acts upon the bar 96 attached |25 of the valve 14 and a pipe |26. The sumps of the pumps 10' and 1| are connected together by an'oil level equalizing pipe |21..-

At a predetermined point in 4the upward or to the rocker arm 83 and actuates the latter in a counter-clockwise direction to shift the valve from the pump 1I is directed by the pipe H6, v

chamber ||1 of the valvei'15 and pipe I2| to the upper end of the right cylinder 69. Thus, the

left and right plungers 53 will be moved upward-lk 1y and downwardly, respectively, as viewed in Fig. 4, and in an identical manner to that previously described in connection with their downward and upward movement, fused alloy will be pumped into the extrusion chamber |4 and drawn into the bore 5| of the right extrusion pump 23. In the continuedoperation of the apparatus the plungers 53 serve to continuously pump fused alloy into the extrusion chamber I4 and to draw fused alloy from the supply into the bores 5| of the extrusion pumps 29.

It is to be noted that the pipes ||5 and |2| connected tofopposite ends of the right cylinder 69 and the pipes |20 and |24 connected to opposite ends of the left cylinder 69'serve alternately as oil pressure supply pipes,to the cylindersfor moving the associated plungers 53 during their forward pumping and return strokes, respectively. Also, each pair of pipes connected to opposite ends of each cylinder serve alternately to direct the exhaustA oil from the cylinders to the sumps of the associated pumps.

In an intermediate position (not shown) of the valve pistons 16 and 11 occurring during the period of shifting thereof to either their extreme left or right hand positions-the pump 10 which f serves solely to supply high, pressure oil for the forward strokes of the plungers will direct pressure oil by way of the pipe I3 and the chamber ||4 of the valve 14 simultaneously through the pipes |24 and |I5 into the lower ends of both I cylinders-69. This results in an overlapping of the forward movement of both plungers 53 and for a period sufficient to insure that the extrusion chamber |4 is continuously supplied with fused alloy to be extruded. Furthermore, by moving both plungers 53 forwardly bythe pressure uid supplied bythe single constant displacement pump 10, the sum of the forwardA stroke displacement rates of the plungers isconstant and thus the vfused alloy ,is supplied to the extruding chamber at a/constant rate, or unvarying velocity. i l

During the period when both of the plungers 53 are moving forwardly the exhaust oil from the upper ends of the cylinders 69 is returned to the sump of the pump 1| by way of the pipes |20 and |2l, the chambers ||1 and |22 of'thevalve 15 and the pipe |23, the oil from the pump 1| being by-passed to the sump of the pump 1| t for controlling the condition of the alloy within the extruding chamber by regulating the heating and cooling mediums supplied thereto. This mechanism is responsive directly to the pressure of the oil in the pipe II3 which directs high pressure oil from the pump 10 to the cylinders 69 for the forward pumping strokes of the plungers 53. At higher temperatures in the exgreater pressures, respectively, in the high prest sure pipe |I3 and this varying pressure therein is used to predeterminedly control the heating medium supplied to the chamber I4 and the coolant supplied to the die holder 4| so that the alloy in the extruding chamber I4 is maintained in a fused state until very near the extruding point, whereby the extruding pressure is reduced to a practicable minimum.

Referring particularly to Fig. 5, the pipe ||3 which directs high pressure oil from the pump 10, has connected thereto, at a point in advance of its connection to the valve 14, a pipe |40 which constantly directs the high pressure oil to an adjustable spring loaded diaphragm |4|. A plunger |42 of the diaphragm is pivotally connected to one end of a pivoted bar |43 arranged to alternately make and break a circuit controlled by spring contacts |44. The spring contacts |44 are included in one side of a suitable source of electrical power (not shown) which is connected to line vwires |45 and |46, respectively. Connected in parallel to the line wires |45 and |46 are solenoids |41 and |48, the cores of which are connected to stems of spring loaded slide valves |5| and |52, respectively.v 'I'he valve I5| controls the volume of gas directed to a burner |50, which includes a pilot light, associated with the inlet pipe 98 -of the heating chamber 91 surrounding the extrusion block I3, a blower being indicated at |53 for circulating the heat from the gas burner around the heating chamber 91 and vthrough the exhaust pipe 98 arranged opposite the inlet pipe. 'Ihe valve |52 controls the volume of fluid coolant directed to the die holder 4| by the pipe |06, the coolant being circulated through the die holder in the manner hereinbefore described. A throttle valve |54 is included in a pipe |56, conneoting the gas slide valve I 5| and the burner |50, and a throttle valve |55 is provided in the pipe |06 connecting the coolant slide valve |52 and the die holder 4| for controlling the volume of gas and coolant being directed to the burner and die holder, respectively.

The valves |54 and |55 are initially adjusted to permit the passage therethrough of a suicient volume of gas and coolant, respectively, to provide the desired temperature condition in the extrusion chamber I4. The spring of the diaphragm |4I is also adjusted so that the plunger |42 is urged downwardly but not with a force 'great enough to overcome the high pressure in the pipe |40 which normally actuates the diaphragm to hold the plunger |42 in its upper position. Consequently, the bar I43 will hold the spring contacts |44 engaged, thus holding closed an electrical circuit through the line wires |45 and |46 to the solenoids |41 and |48. When the valve |5| is opened the valve |52 is closed and vice versa.

In the operation of the extruding apparatus, if the pressure inthe pipe |40 drops due to a reduction of the pressure in the extrusion chamber |4 caused by too high a temperature in the chamber the diaphragm plunger |42 will move downwardly permitting the engagement between the spring contacts |44 to be broken and thus opening the energizingv circuits through the solenoids |41 and |48 and consequently closing the gas valve |5| and opening the uid coolant valve |52. chamber I4 to be lowered and due to the greater resistance to extrusion Iof the alloy, the temperature of which has also been lowered, the pressure in the pipe |40 will rise and the dlaphragm plunger |42 will be moved upwardly resulting in the closing of the circuits to the solenoids |41 and |48. The solenoids |41 and |46 are thus energized causing the fluid coolant valve |52 to be closed and the gas valve |5| to be opened and thereafter whenever the pressure in the extrusion chamber I4 drops or rises an appreciable amount from a predetermined pressure the control circuit will automatically serve to correct this condition. Thus, the possibility of any alloy passing in its fused state from the extrusion This will cause the temperature in the l chamber I4 is prevented and the pressure needed f to extrude `the comparatively small slug continually being formed at the extruding end of the chamber is maintained at a practicable minimum. v

In an alternative form of temperature control mechanism, illustrated fragmentarily in Fig. 6, the volume of gas directed to the burner |50 and the volume of fluid coolant directed to the die holder 4|v are simultaneously gradually varied in accordance with pressure variations in the high pressure oil pipe |40, as distinguished from the intermittent completely on or off method described hereinbefore in connection with Fig. 5.

Referring to Fig. 6, an adjustable spring loaded diaphragm |60 is in communication with the high pressure oil pipe |40. A plunger IGI ofthe diaphragm is pivotally connected to one end of a lever |62 fulcrumed at |63, the opposite end of the lever being pivoted to the stems of oppositely arranged spring loaded slide valves |64 and |65 for controlling the volume of gas and coolant directed by the pipes |56 and |06 to the burner |50 and the die holder 4I, respectively. The valves |64 and |65 are adapted to control the gas and coolant reversely, that is, when the gas volume is diminished the coolant volume is increased and vice versa. With this arrangement due to the leverage transmitted through the lever |62 to the stems of the valves |64 and |65 from the movement of the diaphragm plunger |6I, when the pressure in the pipe |40 varies from a predetermined desired pressure, a gradual change either more or less, in the volume of gas passing through the valve |64 to the burner |50 is effected and simultaneously therewith a gradual change, either less or more, in the volume of coolant passing through the valve |65 is effected. This causes a corresponding change in the temperature in the extrusion chamber I4, which temperature determines the extruding pressure required.

In the temperature control mechanisms shown in Figs. 5 and 6 both the gas and coolant volumes supplied to the extrusion head are responsive 5 and 6 are controlled from the pressure in the tus Will'be clearly understood from the above detailed description. Briefly, the operation is as follows: The fused alloy is continuously supplied to the extruding chamber Il at a constant rate by thehydraulically actuated extrusion pumps 28 in the manner hereinbefore described.

During the movement of the fused alloy from the inlet end of the extruding chamber Il to the discharge opening I5 thereof, effected by the continuous introduction of fused matter into the chamber, the alloy is maintained in a fused state until very near the extrusion point by the heating medium supplied to the extrusion head I I, a cornparatively small slug of the alloy being continually formed adjacent the extrusion point by the introduction of a coolant into thehead solely at this point. The slug so formed is continuously extruded at a constant rate, or unvarying velocity by the continuous introduction of fused alloy into the chamber. The temperature of the alloy within the extrusion chamber is accurately controlled through the regulation of the heating.

and cooling mediums by the mechanism hereinbefore described, which is responsive directly to the pressure of the oil in the pipe H8 directing high pressure oil from the pump I8 to the hydraulically actuated extrusion pumps 28.

Although the invention, as herein illustrated and described, is'particularly applicable to the forming of a lead alloy sheath around cable cores,

it should be understood that the hydraulic system for driving the piston type pumps and the other novel features of the invention are capable of various other applications within the scope of the appended claims.

What is claimed is: v

. 1. In an extruding apparatus, an extruding chamber, a plurality of piston type pumps for supplying said chamber with matter to be extruded therefrom, and constant volume fluid pressure means for-driving the pistons of said pumps, comprising means controlling the application of force to said pistons in such a manner that the sum ofv their displacement rates is constant.

2. In an extruding apparatus, an extruding chamber, a plurality of piston type pumps for supplying said chamber with matter. toV befex'- truded therefrom, means for supplying a pressure iiuid to said pumps at va. constant rate for moving the pistons ofthe pumps in one direction in succession with overlapping strokes, and means for controlling said pressure fluid so that the sum of the speeds of the pistons in said direction is constant.

3. In combination, a chamber having a dis chamber, a plurality of extruding cylinders for supplying said' chamber with matter to be extruded therefrom, an extruding plunger for each cylinder pressure fluid actuated means individual l to each plunger for moving the plungers in succession with overlapping strokes, ad means for controlling the pressure iluld actuated means so that the sum of the displacement rates of the plungers is constant.

5. In an extruding apparatus, an extruding chamber, a pair of extruding cylinders for continuously supplying said chamber with matter to be extruded therefrom, an extruding plunger for each cylinder, pressure iluid actuated means individual to each plunger for moving the plunger so that their forward strokes overlap, and a single constant displacement pump for supplying the pressure fluid for the forward strokes of the plungers so that the sum of their displacement rates is constant. l

6. In an extruding apparatus, an extruding chamber, means for continuously supplying-the chamber with matter to be extruded comprising a plurality of pump cylinders communicating with thechamber, a plunger for each cylinder, a pressure iluid system, including fluid actuated means individual to each plunger for reciprocating them, valve mechanism for directing the pressure uid simultaneously and then individually to the cylinders for driving the plungers with their forward pumping strokes overlapping, means responsive to the movements of the plungers for actuating the valve mechanism, and a single constant displacement pumpcommunicating with the valve mechanism for furnishing pressure uid for the forward pumping strokes of the plungers.

7.' In an extruding apparatus, an extruding chamber, means for continuously supplying the chamber with matter` to be extruded comprising a pair of pump cylinders communicatingl with the chamber, a plunger for each. cylinder, and 'a pressure fluid system, including a cylinder individual to each plunger. a piston operating in `said cylinder and connected to said plunger, means for directing pressure uld to said cylinders for vdriving said pistons and thereby the plungers withtheir forward pumping strokes overlapping, and a single constant displacement pump communicating with said directing means for furnishing pressure -iiuid for the forward pumping the cylinder bore, a plunger for each cylinder bore, and means for reciprocating the plimger.

9. In an extruding apparatus, a block having an extruding chamber therein and an inlet aperl ture for the chamber at its rear end, an outwardlyextending shoulder portion o n the block at its forward end, means for supplying the chamber with matter to be extruded, and means for supporting the matter supplying means in communicating alinement with the inlet aperture, comprising a plurality of cooperating means surrounding the block, one of said cooperating means having an end portion abutting the rear end wall of the block, means for securing the matter supplying means to said end portion, another of laid 15- cooperating means abutting a rear surface of said shoulder portion and shrunk over the forward end of the block, and means for securing the cooperating means together.

10. In an extruding apparatus, a cylinder having an extruding `chamber therein and an inlet aperture for the chamber at its rear end, a circumferential iiange on the cylinder at its forward end, means for supplying the chamber with mattei` to be extruded, means for supporting the matter supplying means in communicating alinement with the inlet aperture comprising a housing surrounding the cylinder with its forward end longitudinally spaced from a rear annular surface of said flange and having a rear wall abutting the rear end wall of the cylinder, an annular member surrounding said iiange in abutting relaf tion with the rear" annular surface thereof and shrunk over the forward'end of the cylinder, means for securing the housing and annular member together, and means forsecuring theI matter supplying means to the housing.

ll. In an extruding apparatus, a block having an extruding chamber therein kand an inlet aperture for the chamber at its rear end, an outwardly extending shoulder portion on the block at its forward end, means for supplying the chamber with matter to be extruded, and means for supporting the matter supplying means in communicating alinement with the inlet aperture, comprising a plurality of cooperating means surrounding the block, one of said cooperating means having an'end portion abutting the rear end wall of the block and provided with an inner channel cooperating with the outer surface of the block to provide a heating chamber for the extruding chamber, means for securing the matter supplying means to said 'end portion, another of said cooperating means abutting' a rear surface of said shoulder portion and shrunk over the forward end of the block, and means for securing ,the cooperating means together.

12. In an extruding apparatus, an extruding chamber having an extrusion aperture at one end and a plurality of inlet apertures at the opposite end, means communicating with the inlet aperpreventing the formation of irregularities-in end of said solidied portion. I

13.- In an extruding apparatus, an extruding chamber having an extruding aperture, means for supplying said chamber withjused matter to be extruded, pressure uid actuated means including a pressure fluid line for applying a predeter-i mined pressure to the matter in the chamber to extrude it therefrom, and means operatively associated with said line and responsive to variations fthe 14. In any extruding apparatus, an extrudlng chamber having an extruding aperture, means for supplying said chamber with fused matter to be extruded, means for subjecting the fusedmatter in a portion of said chamber to heat to maintain it in a fused state, means for subjecting the fusedv matter in another portion of said chamber to a cooling medium to cause the solidiiication of said portion, pressure fluid actuated means including a pressure iuid line for extruding the solidified matter through the aperture by the introduction under a predetermined pressure of fused matter into said chamber, and means operatively associated with said line and responsive to variations in the pressure therein for regulating the heating and cooling of the matter in said chamber.

15. In. an extruding apparatus, an extruding t ference, and valvesv associated with the ports for preventing back flow of the matter from and into the cylinder bore respectively.

16. In an.' extruding apparatus, an extruding chamber having an extruding aperture, means for Y supplying said chamber with fused matter tobe extrude it therefrom, and means. including a pressure fluid actuated element communicating with said line responsive to variations in the presy sure therein caused by variations in the condition of the matter within said chamber for varying the temperature of the matter within said chamber.

17. Ill/an extruding apparatus, an extruding cber having an extruding aperture, means for supplying said chamber with fused matter to be extruded, pressure uid actuated means including a pressure fluid line for applying a predetermined pressure to the matter in the chamber to extrude it therefrom, and means including a pressure fluid actuated element communicating with said line and an electrical circuit controlled by said element responsive to variations in the condition of thei matter within said chamber forv varying the temperature of the matter Within saidv chamber.

18. In an extruding apparatus, an extrusion i chamber, a pair of extrusion cylinders communieating with said chamber, an extrusion piston in each of said cylinders, a'fiuid actuatedmotor for reciprocating each of said extrusion pistons, said motors each comprising a cylinder in longitudinal alignment with an extrusion cylinder and a motor pistons forwardly at lsuch speeds that the sum of tharates of movement is equal to the normal rate 1 of movement of either piston in the forward direction until said piston completes its forward stroke, at whichinstantsaid control means operates to supply said iiuidA to the other piston to move it forwardly at its normal constant rate.

' EINER w.

20 cylinder bore and substantiallywithin its circum- 

